Office chair



FIG. 1 is a perspective view of an office chair, showing my new design;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a left side view thereof;

FIG. 5 is a right side view thereof; and,

FIG. 6 is a top view thereof.

The broken lines depict environmental subject matter, are for illustration only and form no part of the claimed design. 

CLAIM The ornamental design for an office chair, as shown and described. 